Isolating switch

Abstract

In this isolating switch, which is suitable for electrically isolating and connecting components of gas-insulated encapsulated switching stations under, at the most, low load conditions, the fixed contact member (1) is provided with a central trailing contact (2) which ends in a contact member (7). It is coaxially surrounded by a circle of rated-current fingers (3a-h) and a fixed contact shielding electrode (15). The central contact rod (5) of the movable contact member (4) is coaxially surrounded at a distance by a shielding electrode (6) which is also movable. In order to prevent undesirable flash-overs, in particular flash-overs at the encapsulation, the rated-current fingers (3a-h) are in contact with the contact rod (5) in the area surrounded by the shielding electrode (6) which is also movable. They are mounted to be rotatable and have forces applied to them which press their end members (14a-h) radially inward. The contact member (7) is constructed as a shield-like plate having a front face (21) which is domed forward towards the movable contact arrangement (4). When the trailing contact (2) is pushed back, the rated-current fingers (3a-h), which are located behind the front face (21) when the trailing contact (2) is pushed forward, project through openings (22a-h) in the contact member. The contact rod (5) and, on its inside, the shielding electrode (6) which moves along with the former are provided with circumferential grooves (19,20).

I claim: 
     
       1. Isolating switch containing an essentially rotationally symmetric fixed contact member (1) having a centrally arranged trailing contact (2) ending in a contact member (7), and a ring, coaxially surrounding the fixed contact member (1), of rated-current fingers (3a-h; a likewise essentially rotationally symmetric movable contact member (4) having a centrally arranged contact rod (5) and a shielding electrode (6) both of which are movable along with said movable contact member (4), said shielding electrode (6) coaxially surrounds at a distance at least the region of said contact rod (5) which is located directly behind the end of said movable contact member (4) facing said fixed contact member (1), characterised in that said rated-current fingers (3a-h) are arranged and constructed in such a manner that their end members (14a-h) contacting said movable contact member (4) are positioned between said contact rod (5) and said shielding electrode (6) during the switching-on process.   
     
     
       2. Isolating switch according to claim 1, wherein said contact rod (5) has, directly behind its end facing said fixed contact member (1), a peripheral groove (19). 
     
     
       3. Isolating switch according to claim 2, wherein said shielding electrode (6) movable with said contact rod (5) has, at its inside facing said contact rod (5), a peripheral groove (20). 
     
     
       4. Isolating switch according to claim 1 wherein said fixed contact member (1) surrounded by a fixed contact shielding electrode (15) having an opening (16) towards said movable contact member (4) into which opening said movable contact member (4) projects in the on-position; said contact member (7) of said trailing contact (2) constructed as a shield-like plate having a front face (21) which is domed forward towards said movable contact member (4) and which, in the off-position, essentially covers the opening (16) of said fixed contact shielding electrode (15); said front face (21) having openings (22a-h) through which, in the on-position, with said trailing contact (2) pushed back, said rated-current contact fingers (3a-h) project whereas, in the off-position, the said rated-current fingers (3a-h) are located behind the domedforward front face (21). 
     
     
       5. Isolating switch according to claim 4, characterised in that said rated-current fingers (3a-h) are mounted to be rotatable and are loaded by forces by which their said end members (14a-h) are pressed radially inwards.